(a) Field of the Invention
The present invention relates to a thin film transistor array panel for a liquid crystal display including a pixel electrode.
(b) Description of the Related Art
A liquid crystal display (“LCD”) is one of the most widely used flat panel displays. An LCD includes two panels having field-generating electrodes and a liquid crystal layer interposed therebetween and controls the transmittance of light passing through the liquid crystal layer by realigning liquid crystal molecules in the liquid crystal layer with voltages applied to the electrodes.
One of the most commonly used LCDs provides a plurality of planar field-generating electrodes on one panel with switching elements switching the voltages applied to the electrodes and one large planar field-generating electrode on the other panel, which is applied with a fixed voltage or two swinging voltages. Thin film transistors (“TFTs”) are usually used as the switching elements, and the panel including the TFTs is called the “TFT array panel.”
The planar field-generating electrodes provided on respective panels generate electric field perpendicular to the panels. Some of the electric field lose that perpendicularity near the edges of the electrodes.
A typical LCD further includes an alignment layer for determining initial alignments of the liquid crystal molecules. One type of the alignment layer forces the director of the liquid crystal material to be parallel to the surface of the alignment layer (which is called homogeneous alignment), while another type forces the director to be normal to the surface (which is called hemeotropic alignment). A proper surface treatment of the alignment layer such as rubbing and light exposure controls the tilt directions of the liquid crystal molecules. For example, the rubbing in a direction enforces the major axes of the liquid crystal molecules to tilt in that direction.
The combination of the irregularity of the electric field near the edges of the field-generating electrodes and the compulsive alignment of the liquid crystal molecules using the surface treatment of the alignment layer may result in loss of control for the liquid crystal molecules. This effect is called disclination, which causes light leakage.